Modular representation of urban traffic systems based on hybrid Petri nets

The problem of providing a modular representation of urban traffic and roadways by means of Petri nets is addressed. A modular modelling methodology is presented. After defining the urban traffic model and identifying each one of its components, it is possible to define for each element a hybrid Petri net module (HPNM), and provide an internal representation of it at a desired level of detail. A synthesis procedure allows one to join the single modules and provide the representation of the whole urban roadway considered in terms of hybrid Petri nets. An interesting characteristic proper to the proposed methodology is the complete independence of HPNMs from their internal representations. This allows one to change the model without any effort by increasing/decreasing the specified level of detail of some HPNMs making up the HPN-model of the whole system.